Please your thoughts Combis or Multis the difference

So I been getting into more of the Combis Patches and learning to make my
own. Since I run HALion 7 as a instrument on each Track would a Multis
be something better to do I’m still trying to learn the difference, as if a
setting or feature works with Combis and not Multis as Combis is a
one instrument Slot and Multis are separate instruments, Please and Help
thoughts ideas

any info would be great

You can save/load a layer, program or a multi preset.

Not quite sure what you mean by combi. Multi preset saves the state of the whole plugin instance with all the programs you have loaded in the slots and their settings. It can be useful when using the standalone version or when you have a bunch of programs you want to save and recall together.

Whether to use instrument tracks with one program loaded or a single instance of HALion with multiple slots and midi tracks is up to you and what workflow you prefer.

Here is a thread discussing similar topic:
Is there any benefit in using Track instruments in Halion when composing a whole orchestra? - Virtual instruments / HALion - Steinberg Forums

The two libraries HALion Sonic 2 Combis, HALion Sonic 3 Combis load any of them
its one instrument patch that consist of multiple layers Trium Auron BBox for example.
Trium could have a ARP playin Auron will be just a Pad sound and BBox playing a pattern
all loaded into one slot. I’m familiar with the concept you describe. The Track or Rack
instruments I have done both in the past I still haven’t decide which one is good for me
there is such a debate on which to use